The goal of this project is to develop and test the feasibility of an eyetracking system for assessment of language comprehension in people with stroke and brain injury. Most people who have had a stroke or brain injury have deficits that may impair their ability to respond, or to respond correctly, when traditional tests of linguistic comprehension are administered. This novel assessment system, called the Eyetracking Comprehension Assessment System (ECAS), will enhance the validity of language comprehension testing for people whose comprehension is poorly or inaccurately accessed via traditional assessment methods. ECAS will be comprised of bundled eyetracking and user interface hardware, stimulus delivery software, analysis software, and an assessment protocol incorporating two new standardized tests of auditory comprehension designed for this application. The equipment and methods require further research and development before the system may be made available to the general research community or to clinical enterprises. The primary objectives of Phase I fall into two interrelated areas: (A) ECAS equipment and operating procedure development and (B) empirically-based refinement of comprehension assessment methods and feasibility testing. The specific aims in the development of equipment and operating procedures are to: (1) test single-eye versus binocular eyetracking in terms of usability, accuracy, reliability and cost;(2) upgrade the existing, rapid- prototype ECAS software to a production quality;(3) develop real-time displays for monitoring eye movements superimposed on the visual stimuli;(4) develop displays to show intermediate scoring results during the test and final results immediately following the test;(5) develop a simple, touchscreen-control interface for the clinician administering the test;and (6) develop and refine a set of carefully controlled visual stimuli image stimuli for use in ECAS testing. Specific aims for refining and testing ECAS comprehension assessment methods are to: (7) establish the validity and reliability of ECAS methods through experimentation with (a) adults without any neurological disorder and (b) adults with aphasia due to cerebrovascular accident (stroke);(8) establish normative data for two standardized tests of auditory comprehension incorporating new testing protocols and hardware and software developments;and (9) determine optimal scoring criteria and means of data interpretation for individual patients. All specific aims will be addressed through an interdisciplinary team science approach. PUBLIC HEALTH RELEVANCE: Knowing how much a person understands when listening to others speak is essential for appropriate treatment planning, socialization, and major life decisions related to living arrangements, financial management, legal status, and potential for return to work, educational, and leisure activities. The proposed ECAS system will enhance the validity of language comprehension assessments for people whose comprehension is poorly or inaccurately accessed via traditional methods. The novel system will be helpful for people with a wide range of neurological disorders.